The problem with higher level math is that there are an infinite amount of correct answers, but there are infinitely more incorrect answers at the same time. The problems would be similar to "Go grab your dad a beer from the store," and after everything is said and done, you end up on Neptune, amirite?

Imagine a plane in space. In order to describe a plane on the coordinate axes, you need a vector that is orthogonal (perpendicular) to the plane because it shows the direction of the plane. Imagine you're given 3 points on the plane: A, B, and C. In order to find the orthogonal vector you need to do the cross product between two vectors on the plane. You can do AB x BC, you can do BA x CA etc. Each way you do it will come up with a different answer in terms of what you write down, but it will still be describing the exact same plane in space.

Or a more simple example, just multiply both sides of the equation by anything you want. y=mx+b describes the same line as 2y=2mx+2b